Foreign bodies within the nasolacrimal system, eg grass awn.
Bacterial conjunctivitis with extension into the nasolacrimal sac or duct. Most common isolates are Staphylococcus , Streptococcus , E. coli , Enterobacter , Pseudomonas , and Proteusspp .
Dental disease with extension of infection from the tooth root into the nasolacrimal duct.
Infection secondary to other obstructions of the duct, eg trauma, tumor, stenosis, cysts, etc.
Rarely, fungal infections of the nasolacrimal duct.
Predisposing factors General
Outdoor or hunting dogs for foreign bodies .
Pathophysiology
Inflammation of the lacrimal sac or nasolacrimal duct.
Presence of foreign body results in inflammation and secondary bacterial infection.
Bacterial infections may extend into the nasolacrimal sac and duct from adjacent tissues.
Timecourse (incubation, duration)
Symptoms may develop in 5-7 days.
Duration may be prolonged because the disease is often unresponsive to topical antibiotics.
Pressure on the medial canthus results in purulent material extruding from the lower punctum.
Occasional swelling over the lacrimal sac just beneath the medial canthus; may be painful.
Excoriation of the skin near the medial canthus from accumulation of ocular discharge.
Diagnostic investigation
Ophthalmic examination
To rule out other causes of purulent ocular discharge, such as ulcerative keratitis , keratoconjunctivitis sicca , bacterial conjunctivitis .
To rule out epiphora and causes of epiphora .
Fluorescein stain applied to the cornea does not appear at the nose or the back of the throat. This test does not confirm blockage of the nasolacrimal duct in all animals, however, and is not diagnostic of dacryocystitis.
Microbiology
Bacterial culture of discharge expressed from the lower punctum.
Cannulation
Cannulation and flushing of the nasolacrimal duct is the easiest method to confirm dacryocystitis.
A nasolacrimal cannula is inserted into the upper punctum and saline is flushed into the cannula, observing for purulent or foreign material to extrude from the lower punctum.
After flushing the upper puncta, the lower punctum is cannulated and the upper punctum is occluded with digital pressure. The cannula is flushed with saline and the nose is observed for passage of purulent material and foreign debris.
Resolution of signs after flushing and administration of topical antibiotics may confirm the diagnosis.
Radiography
Plain radiographs of the skull taken under general anesthesia may be helpful in identifying tooth root disease, bony lysis or proliferation, cystic changes in the area of the lacrimal sac, and nasal disease.
Dacryocystorhinography
Is sometimes required to confirm the diagnosis and identify a cause.
Plain radiographs of the skull are taken with the animal under anesthesia. If no abnormalities are found, then a positive contrast procedure is performed.
One-half to two milliliters of aqueous positive contrast material (eg Hypaque) is infused into the upper punctum using a lacrimal cannula or catheter, while the lower punctum is occluded.
Lateral (affected side up) and dorsoventral radiographs are repeated after the infusion.
Helps to identify distention of the nasolacrimal sac; abnormal position, deviation, dilatation, rupture or stenosis of the duct; and sometimes abnormalities of the canaliculi.
Confirmation of diagnosis Discriminatory diagnostic features
History.
Clinical signs.
Ophthalmic examination.
Definitive diagnostic features
Nasolacrimal duct flushing: non-patency or foreign body flushed from duct, resolution of signs after flushing.
Nasolacrimal flushing is performed as outlined above and followed by a topical antibiotic solution.
Systemic antibiotics may also be needed for evidence of nasal or dental disease, excoriation of the skin, etc.
Non-responsive cases may require treatment via an indwelling nasolacrimal cannula:
Polyethylene, silastic or polyvinyl catheter tubing is inserted and sutured to the skin of the face, adjacent to the medial canthus and nares.
Cannula is left in place for at least 3 weeks.
Uncannulated punctum isflushed with antimicrobial agent .
Topical antibiotic solutions are continued and are sometimes combined with topical steroids.
Dacryocystotomy may also be considered in refractory cases, especially if a foreign body may be lodged in the lacrimal sac.
Involves opening the lacrimal sac by drilling through the bone over lying the area.
The sac is cannulated and a catheter is left in place prior to surgically opening the sac to help in identification of the sac. The sac is entered, flushed and any foreign material is removed.
It is then sutured closed with the cannula left in place, and followed by topical and systemic antibiotics.
Whitley R D (2000) Canine and feline primary ocular bacterial infections.Vet Clin North Am Small Anim Pract30 , 1151-1167.
van der Woerdt A, Wilkie D A, Gilger B C et al(1997) Surgical treatment of dacryocystitis caused by cystic dilation of the nasolacrimal system in three dogs.JAVMA211 , 445-447.
Laing E J, Spiess B & Binnington A G (1988) Dacryocystotomy - a treatment for dacryocystitis in the dog.JAAHA24 , 223-226.
Lavach J D, Severin & G A Roberts (1984) Dacryocystitis - a review of 22 cases.JAAHA20 , 463
Johnston G R, Feeney D A (1980) Radiology in ophthalmic diagnosis.Vet Clin North Am Small Anim Pract10 , 317-337.
Other sources of information
Munger R J (2002) Disorders of the lacrimal and nasolacrimal system. In: Morgan R V, Bright R N, Swartout M S (eds) Handbook of Small Animal Practice. 4th Ed. W B Saunders, Philadephia, pp. 954-963.
Vetstream contributor(s)
Dr Paul Gerding DVM MS DipACVO , Department of Veterinary Clinical Medicine, 1008 West Hazlewood Drive, Urbana, IL 61802-4795, USA.
Dr Rhea V Morgan DVM DACVIM DACVO , Smoky Mountain Veterinary Services, Walland TN, USA
